During pulmonary function testing, a rebreathe system is employed to perform various measurements of a patient's respiratory system. Current rebreathe circuits include a series of components that include a breathing valve assembly which may include expire- and inspire-only valves, a reservoir, a carbon dioxide absorber, and a circulation fan that pulls air from the reservoir, pushes the air through the carbon dioxide absorber and then back into the reservoir. Alternatively, the circulation fan may also pull air from the carbon dioxide absorber and then push air into the reservoir. A rebreathe circuit supports several pulmonary function tests including, but not limited to, a closed circuit helium functional residual capacity (FRCHE) test, a nitric oxide diffusing capacity (DLNO) test, a diffusing capacity of carbon monoxide (DLCO) test, and other tests that are used to diagnose lung function conditions. During the circulation of air, carbon dioxide is removed from the gases as they pass through the carbon dioxide absorber.
Components of rebreathe systems can be single use (i.e., disposable) or multi-use. For multi-use rebreathe systems, these components can be isolated from cross-contamination through the use of a barrier filter and, with or without barrier filters, the components need to be cleaned and disinfected periodically so as to prevent cross-contamination between patients and/or remove contamination particles from the components. Independent of being single use or reusable, cleaning and/or disinfecting of the circulation fans can be particularly problematic. Current fans in rebreathe systems are directly coupled to a fan motor and are cumbersome and time consuming to remove for cleaning of surfaces of the fan. Moreover, electrical components of the motor need protection from cleaning and disinfectant solutions so as to prevent damage thereto. If not properly cleaned, parts of the rebreathe circuit can be exposed to cross-contamination from one patient to the next patient.